1. Field of the Invention
This invention relates to the power laser generators in which it is possible to control the angular direction of the output beams.
2. Discussion of the Background
In many fields, for example, telemetry and missile guidance, a laser beam, whose space-time coherence makes it possible to define a "small and immaterial line" over a relatively long path, is used most often as a reference element.
For terrestrial missile guidance over short distances, for example, a "helium-neon" type laser generator of several milliwatts of power is used. The beam defined by this type of generator is fine enough to be used as a reference for guiding or telemetering. Moreover, the laser generator is small and compact enough to easily, make possible the orientation, along a given direction, of its output beam. For this purpose, it is sufficient to mount the laser generator on a plate and to move this plate, by motors, along two or three axes. However, this use gives the desired result, only if the necessary angular displacement velocity is not very great.
In particular, for terrestrial guidance of missiles having to more relatively quickly, deflection cells have been made which are placed on the laser beam itself, at the output of the laser generator, and controlled electrically as are, for example, the acoustooptical static deflectors well known to one skilled in the art. The advantage of these deflectors is that they very quickly respond to the deflection orders which are given to them. On the other hand, they exhibit a major drawback namely, that of being able to only deflect low-power laser beams. Actually, in the case of the deflection of power beams, the deflectors are deteriorated very quickly by these beams themselves and their effectiveness decreases significantly when the given deflection angle increases, i.e. the power of the deflected beam diminishes as a function of the increase of the deflection angle.